Afghan doctors, receive a wounded man from an ambulance after a roadside bomb struck, at a hospital in Kandahar, south of Kabul, Afghanistan, Monday, April 7, 2014. A roadside bomb killed at least 15 people traveling in vehicles that had been diverted from a main road Monday after an earlier attack in southern Afghanistan, officials said. (AP Photo/Allauddin Khan)

Afghan doctors, receive a wounded man from an ambulance after a roadside bomb struck, at a hospital in Kandahar, south of Kabul, Afghanistan, Monday, April 7, 2014. A roadside bomb killed at least 15 people traveling in vehicles that had been diverted from a main road Monday after an earlier attack in southern Afghanistan, officials said. (AP Photo/Allauddin Khan)

Family members help a wounded man at a hospital after a roadside bomb in Kandahar, south of Kabul, Afghanistan, Monday, April 7, 2014. A roadside bomb killed at least 15 people traveling in vehicles that had been diverted from a main road Monday after an earlier attack in southern Afghanistan, officials said. (AP Photo/Allauddin Khan)

Medics close a coffin of a person killed from a roadside bomb in Kandahar, south of Kabul, Afghanistan, Monday, April 7, 2014. A roadside bomb killed at least 15 people traveling in vehicles that had been diverted from a main road Monday after an earlier attack in southern Afghanistan, officials said. (AP Photo/Allauddin Khan)

Hospital staff carry the coffin of a person killed from a roadside bomb, at a hospital in Kandahar, south of Kabul, Afghanistan, Monday, April 7, 2014. A roadside bomb killed at least 15 people traveling in vehicles that had been diverted from a main road Monday after an earlier attack in southern Afghanistan, officials said. (AP Photo/Allauddin Khan)

Afghan doctors and medics treat a wounded man at a hospital after a roadside bomb in Kandahar, south of Kabul, Afghanistan, Monday, April 7, 2014. A roadside bomb killed at least 15 people traveling in vehicles that had been diverted from a main road Monday after an earlier attack in southern Afghanistan, officials said. (AP Photo/Allauddin Khan)

Buy AP Photo Reprints

KANDAHAR, Afghanistan (AP) â€” A roadside bomb killed at least 15 people traveling in vehicles that had been diverted from a main road Monday after an earlier attack in southern Afghanistan, officials said.

The blast came after a relatively calm weekend in which no major attacks were reported as Afghans voted for a new president and provincial councils.

The Taliban had threatened violence to disrupt Saturday’s vote, and staged a series of high-profile assaults in the preceding weeks. But security forces tightened their grip and only sporadic attacks took place.

The two SUVs carrying the civilians hit the hidden explosives on a side road that was being used because authorities blocked the main road following a suicide bombing targeting a NATO convoy in Kandahar province, the local government spokesman said.

Those killed included a woman, and four other people were severely wounded and in critical condition, according to Dawkhan Menapal, spokesman for the provincial governor. All the passengers were from Uruzgan province to the north of Kandahar and were apparently traveling home when the blast occurred in the Maywand district.

The Taliban claimed responsibility for the earlier attack on Monday but blamed international forces for the roadside bombing, saying the foreign forces were trying to hurt the reputation of the Islamic militant movement by making it look like the Taliban were killing civilians.

The suicide bomber was in a minivan when he detonated his explosives in front of the NATO convoy in the same district. Menapal says no serious casualties have been reported in that attack. The international alliance said it was aware of an incident in Kandahar but has not provided any details.

Electoral officials, meanwhile, remained largely mum about results from Saturday’s historic vote, in which millions of people lined up in the rain, defying fears of violence to cast their ballots. President Hamid Karzai was constitutionally barred from a third term, and excitement was palpable as Afghans voted in what promises to be the country’s first democratic transition of power.

Some candidate forecasts and partial results are expected in the coming days. Noor Mohammad Noor, a spokesman for the Independent Election Commission, said preliminary results were due April 24 and final results will be announced May 14.

With a crowded field of eight candidates, nobody was expected to get the majority needed to win outright. That would force a runoff between the top two vote-getters, which would be held at the end of May.

International and Afghan officials hailed the vote. Observers noted several irregularities, including ballot box stuffing, intimidation and a shortage of ballot papers.

But analysts largely agreed it wasn’t on the scale of the massive vote-rigging in the previous elections in 2009, which led to Karzai’s second term.

The U.S.-based National Democratic Institute, which withdrew its international observers after a deadly bombing at a luxury hotel in Kabul where they were staying, said it fielded a delegation of 101 Afghan staff members who visited 327 polling stations in 26 or the country’s 34 provinces.

“The remarkable turnout along with the significant participation of Afghan election monitors, political parties, women, young people and others bodes well for the credibility of the electoral process,” it said in a statement.